Abstract: PM _2.5 exerts significant impact on the regional environment and human health. Huaihai Economic Zone serves as a core that supports the development of the eastern coastal economic development zone so the analysis of its temporal and spatial characteristics of PM _2.5 and its influencing factors are of great significance to carry out the joint prevention of regional air pollution in the Beijing-Tianjin-Hebei region and the Yangtze River Delta urban agglomeration. Firstly, this paper uses time series analysis to analyze the characteristics of PM _2.5 concentration in the study area. Secondly, spatial analysis is used to analyze the temporal and spatial characteristics of PM _2.5 in the Huaihai Economic Zone. Finally, this paper further explores the influencing factors of PM _2.5 concentration and its spatial heterogeneity by using a geographical weighted regression model based on the spatial autocorrelation characteristics of PM _2.5 in the Huaihai Economic Zone. The results show that: (1)The daily PM _2.5 concentration in Huaihai Economic Zone shows a periodic pulsed fluctuation rule, and the overall trend is “U” shaped, high in winter and autumn and low in spring and summer. The oscillation period of daily PM _2.5 concentration is 2-3 days in a short period and 6-7 days in a long period. (2)The spatial local correlation of PM _2.5 concentration in Huaihai Economic Zone shows a periodic changing rule. Hot spots throughout the year are mainly concentrated in Heze City in the northwest and Xuzhou City in the southwest of the study area while cold spots are mainly in coastal areas. (3)The influencing factors of PM _2.5 concentration in Huaihai Economic Zone mainly include average air temperature, average precipitation, average wind speed, proportion of forest land and road network density. Different factors have significant spatial heterogeneity on the influence of PM _2.5 concentration.